When is the Class in a Class Action Too Big?

This story of the Wal-Mart sex discrimination class action has made recent news. What is of interest to me is Wal-Mart’s claim that the size of the class is too big for litigation and how others feel this case may have a large impact on the practical size of class action lawsuits, in general. This NYT article describes how Wal-Mart has over one million employees, and alleges discrimination against hundreds of thousands of female employees.

Now, from the data breach lawsuits that I am examining (if we consider the class to be all those whose information was lost or stolen) I find an average class size of over 5 million, with a median of 200k and maximum of 130 million. I also count over 15 suits with class sizes greater than one million people. Now, to be fair, I don’t know the portion of classes that were actually certified, and this would likely be very small.

Suddenly, a couple hundred thousand in Wal-Mart’s case doesn’t seem all that big. And yet, I’ve never heard any data breach news story that commented on the class size or how it might question Rule 23 of the Federal Rules of Civil Procedure.

I’d love to hear anyone’s thoughts on why this might be. Is the difference simply that the Supreme Court is involved?